Make Metros Stop for Players
The functionality behind metros checking for and stopping for players and certain vehicles/objects in its path is tied to FLAG_IS_ELECTRIC (index 43) in the metrotrain's vehicles.meta.
warning
As it is part of the basegame vehicles.meta you are not able to directly restream these modifications. This requires SET_VEHICLE_FLAG to be used when the PR implementing it is merged.
Custom vehicles
While it is possible to create a custom vehicle with a different name, be aware that a lot of functionality tied to the metrotrain is hardcoded in gamecode to the metrotrain's hash. This makes the experience less than ideal for players.
Alternative solution
An alternative solution by jnktechstuff:
<Item>
<filename>resources:/LevelMeta/meta/vehicles.meta</filename>
<fileType>VEHICLE_METADATA_FILE</fileType>
</Item>
Source: Discord thread